Radical 1,5-Carbonyl Migration Enabled by Energy-Transfer Catalysis

Carbonyl migrations, primarily mediated by electron transfer, are established in ring expansions and alkene difunctionalizations. In contrast, reactions governed by triplet energy transfer remain underdeveloped, and a 1,5-carbonyl migration via this manifold has been synthetically inaccessible. Here, we disclose a photocatalytic strategy to achieve 1,5-carbonyl migration using visible-light-mediated triplet energy transfer. This operationally simple method delivers valuable 1,6-diketones in high yields with broad substrate scope under mild conditions. Experimental and computational studies support a mechanism involving photoinduced diradical formation, 1,5-carbonyl migration, and isomerization. This energy-transfer-enabled photochemical rearrangement provides a general platform to unlock carbonyl functional group translocation.